Samsung SSD XP941 Review: The PCIe Era Is Here
by Kristian Vättö on May 15, 2014 12:00 PM ESTAnandTech Storage Bench 2013
Our Storage Bench 2013 focuses on worst-case multitasking and IO consistency. Similar to our earlier Storage Benches, the test is still application trace based—we record all IO requests made to a test system and play them back on the drive we're testing and run statistical analysis on the drive's responses. There are 49.8 million IO operations in total with 1583.0GB of reads and 875.6GB of writes. I'm not including the full description of the test for better readability, so make sure to read our Storage Bench 2013 introduction for the full details.
| AnandTech Storage Bench 2013 - The Destroyer | ||
| Workload | Description | Applications Used |
| Photo Sync/Editing | Import images, edit, export | Adobe Photoshop CS6, Adobe Lightroom 4, Dropbox |
| Gaming | Download/install games, play games | Steam, Deus Ex, Skyrim, Starcraft 2, BioShock Infinite |
| Virtualization | Run/manage VM, use general apps inside VM | VirtualBox |
| General Productivity | Browse the web, manage local email, copy files, encrypt/decrypt files, backup system, download content, virus/malware scan | Chrome, IE10, Outlook, Windows 8, AxCrypt, uTorrent, AdAware |
| Video Playback | Copy and watch movies | Windows 8 |
| Application Development | Compile projects, check out code, download code samples | Visual Studio 2012 |
We are reporting two primary metrics with the Destroyer: average data rate in MB/s and average service time in microseconds. The former gives you an idea of the throughput of the drive during the time that it was running the test workload. This can be a very good indication of overall performance. What average data rate doesn't do a good job of is taking into account response time of very bursty (read: high queue depth) IO. By reporting average service time we heavily weigh latency for queued IOs. You'll note that this is a metric we've been reporting in our enterprise benchmarks for a while now. With the client tests maturing, the time was right for a little convergence.
In our most demanding storage test, the XP941 is just amazing. It's about 40% faster than any SATA 6Gbps drive we have tested, which is huge. Obviously it's not the random performance that makes the XP941 shine but the large IO sequential performance where the PCIe interface can be used to its full extent. While most IOs in client workloads tend to be random, the sequential performance can certainly make a big difference and high queue depth random reads can also take advantage of the faster interface.
Facebook
Twitter
RSS
110 Comments
View All Comments
McTeags - Thursday, May 15, 2014 - link
I think there is a spelling mistake in the first sentence. Did you mean SATA instead of PATA? I don't know all of the tech lingo so maybe I'm mistaken.McTeags - Thursday, May 15, 2014 - link
Please disregard my comment. I googled it...BMNify - Thursday, May 15, 2014 - link
sata-e[serial], sata[serial], pata[parrallel] ,SCSI [several, and chainable to 15+ drives on one cable, we should have used that as generic] ,shugart these are all drive interfaces and there are more too going back in the day....metayoshi - Thursday, May 15, 2014 - link
"It's simply much faster to move electrons around a silicon chip than it is to rotate a heavy metal disk."While SSD performance blows HDDs out of the water, the quoted statement is technically not correct. If you take a single channel NAND part and put it up against today's mechanical HDDs, the HDD will probably blow the NAND part out of the water in everything except for random reads.
What really kills HDD performance isn't the just rotational speed as much as it is the track-to-track seek + rotational latency of a random workload. A sequential workload will reduce the seek and rotational latency so much that the areal density of today's 5 TB HDDs will give you pretty good numbers. In a random workload however, the next block of data you want to read is most likely on a different track, different platter, and different head. Now it has to seek the heads to the correct track, perform a head switch because only 1 head can be on at a time, and then wait for the rotation of the disk for that data block to be under the head.
A NAND part with a low number of channels will give you pretty crappy performance. Just look at the NAND in smartphones and tablets of today, and in the SD cards and USB thumb drives of yesteryear. What really makes SSDs shine is that they have multiple NAND parts on these things, and that they stripe the data across a huge number of channels. Just think RAID 0 with HDDs, except this time, it's done by the SSD controller itself, so the motherboard only needs 1 SATA (or other like PCIe) interface to the SSD. That really put SSDs on the map, and if a single NAND chip can do 40 MB/s writes, think about 16 of them doing it at the same time.
So yes, there's no question that the main advantage of SSDs vs HDDs is an electrical vs mechanical thing. It's just simply not true that reading the electrical signals off of a single NAND part is faster than reading the bits off of a sequential track in an HDD. It's a lot of different things working together.
iwod - Friday, May 16, 2014 - link
I skim read it. Few things i notice, No Power usage testing. But 0.05w idle is pretty amazing. Since the PCI-E supply the power as well i guess they could be much better fine grained? Although Active was 5.6W. So at the same time we want more performance == faster controller while using much lower power. it seems there could be more work to do.I wonder if the relative slow Random I/O were due to Samsung betting its use on NVMe instead of ACHI.
iwod - Friday, May 16, 2014 - link
It also prove my points about Random I/O. We see how Random I/O for xp941 being at the bottom of the chart while getting much better benchmarks results. Seq I/O matters! And It matters a lot. The PCI -E x4 interfaces will once again becomes bottleneck until we move to PCI-E 3.0 Which i hope we do in 2015.Although i have this suspicious feeling intel is delaying or slowing down our progression.
nevertell - Friday, May 16, 2014 - link
Can't you place the bootloader on a hard drive, yet have it load the OS up from the SSD ?rxzlmn - Friday, May 16, 2014 - link
'Boot Support: Mac? Yes. PC? Mostly No.'Uh, a Mac is a PC. On a serious tech site I don't expect lines like that.
Penti - Friday, May 16, 2014 - link
Firmware differences.Haravikk - Friday, May 16, 2014 - link
It still surprises me that PCs can have so many hurdles when it comes to booting from various devices; for years now Macs have been able to boot from just about anything you plug into them (that can store data of course). I have one machine already that uses an internal drive combined with an external USB drive as a Fusion Drive, and it not only boots just fine, but the Fusion setup really helps eliminate the USB performance issues.Anyway, it's good to see PCIe storage properly reaching general release; it's probably going to be a while before I adopt it on PCs, as I'm still finding regular SATA or M.2 flash storage runs just fine for my needs, but having tried Apple's new Mac Pros, the PCIe flash really is awesome. Hopefully the next generation of Mac Pros will have connectors for two, as combined in a RAID-0 or RAID-1 the read performance can be absolutely staggering.